My (28F) childhood friend (28F) reached out after 10 years during a mental health crisis, how do I respond?

Basically, an old childhood friend [Tara] with mental health issues texted me out of the blue. We've not had contact in about 10 years.

I had lost her number years ago, and the texts were weird (just "hello," sent at weird times late at night/in the morning) so I assumed it was social engineering and ignored them. However, days later, my mom mentioned that she heard Tara had just checked into a mental health center after a suicide attempt. The texts were still bugging me for some reason, so I reversed the phone number and sure enough it linked to Tara.

My mom later told me heard Tara had been discharged, and sure enough a day later, I get another text saying "it's tara." So I can only assume she was reaching out in the dark for somebody who might care.

I want to reply (and apologize for ignoring her) but I feel so at loss for what else to say. Tara lost a parent to suicide a year ago, and I had wanted to reach out, but I no longer had a way of contacting her. I have no social media, besides reddit, but I regret not trying harder to do so.

We were best friends as children but drifted in our teens, as kids tend to do. I feel sentimental when I think about her, but I've never had a real desire to reconnect in a serious way. She became rather nasty in school, and from what I hear through the grapevine, she hasn't changed much. I still want her to know I care about her.

TLDR: Old friend with whom I've had no contact for 10 years reached out. I feel guilty for not checking in on her after a tragedy in her family. I feel at a loss of what to say.